Fluid translating apparatus



0. sco-r'r I FLUID TRANSLATING APPARATUS Jul 1e 6,

Filed Jan. 16, 1941 INVENTOR OLAV Sco-r'r ATTORN WITNESSES:

Patented June 6, 1944 FLUID TRANSLATING APPARATUS Olav Scott, Springfield, Mass, assignor to Westing'hOllSe Electric &. Manufacturing. Company, East Pittsburgh, Pa., a corporation of Pennsyl vania Application January 16, 1941, Serial No." 374,649

(or. 2s0-s1) 4 Claims.

My invention relates to fluid translating appatus, more particularly to a reciprocating compressor having means for unloading one or more cylinders, and it has for an object to provide an improved unloader construction.

A more particular object is to provide a simple, inexpensive and reliable unloader construction.

These and other objects are effected by my invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming apart of this application, in which:

Fig. 1 is a diagrammatic view of a refrigerat-' ing system including a compressor, shown in elevation, that incorporates my novel unloader construction; and,

-Fig. 2 is a cross-sectional view taken mainly on the line 11-11 of Fig. 1, the plane of the section being partly offset, however, to include one of the cylinders and its suction and discharge ports.

Referring to the drawing in detail, I show a compressor I driven by a motor II, the compressor and motor being enclosed in a common casing. The compressor is part of a refrigerat-' ing system including a condenser I2, 2. thermostatic expansion valve l3, and an evaporator M. The refrigerating system may be used, for example, for air conditioning an enclosure, air being circulated over the surface of the evaporator I4 and conveyed to the enclosure.

The cylinder block or main casting of the compressor Ill is formed with a plurality of cylinders arranged in a row, suction passages i6 arranged on one side of the row and discharge passages ll arranged on the opposite side of the row. These cylinders and passages extend vertically and terminate at their upper ends in the plane upper face of the cylinder block. The compressor further comprises valve plates I8 disposed against the upper plane face of the cylinder block, cylinder heads l9 disposed against the opposite or upper side of the valve plates l8 and bolts 2! securing the cylinder heads to the cylinder block as will be apparent from Fig. 2. I prefer to provide one suction passage l6, discharge passage l'l, valve plate I8, and cylinder head I3 for each pair of cylinders, as more fully shown and described in patent No. 2,134,077 of E. Ehret. But, so far as the present invention is concerned, they may be provided for each cylinder. The valve plate 18 is formed with ports 22 and 23 registering with the passages l6 and I1, respectively. It is also provided with a suction valve port 24 and a'discharge valve port 25 for each cylinder. Movable valve elements 26 and'2l, of any suitable type, such a's'reed valve strips, coop erate with the ports 24 and 25 to provide suction and discharge valves for the cylinder. The cylinder head 19 is formed with a suction chamber or passage 28 providing communication between the port 22 and the'suction valve ports 24 of the pair'of cylinders. It is also formed'with a dis charge chamber passage 29 providing communi cation between the discharge ports 25 of the pair of cylinders and the'port 23. r I

The cylinder head I9 is formed with a cylinder 3| disposed in alignment with the port 22. The. upper end of'the cylinder is closed by a cap 32 which may be screw-threaded into the cylinder. A piston 33 is disposed within the cylinder 3| and is adapted to move downwardly against the upper surface of the valve plate l8 to close the port 22. The piston 32 is biased upwardly by a compression spring 34, the upper end of which abuts against a collar 35 screwthreaded in the piston and the lower end of which abuts against the head of a bolt 36 screw-threadedin the cap 32.

Any suitable fluid under pressure'may be uti-'- lized for actuating the piston 33, such as-oil pressure, from the lubricating oil pump or refrigerant gas from the high pressure side of the refrigerating system, the-latter being employed in the illustrated embodiment. The application of fluid pressure to the upper side of the piston 33 'is controlled by a pilot'valve 38 which includes a casing 39 and a piston valve element 4| as shown in Fig. 1. 'A conduit 42 provides communica--- tion betweenthe casing 39 and the conduiti'43 which conveys the compressed gas from the com-- pressor ID to the condenser l2.' A conduit '44 provides communication between the casing 39 and the crankcase of the compressor which con-' tains refrigerant gas at suction pressure. A conduit 45 and a passage 46 formed in the cylinder head .I 9 provide communication between the'casing 39 and the upper end of the cylinder 3L The valve element 4|, when moved to the left by a spring 41, places the conduits 45 and 42 in communication, and when moved to the right by a solenoid 43 places the conduits 45 and- 44 in communication.

The unloader mechanism just described may be utilized in connection with any desired scheme of partial load operation. For the purpose of example, I show a thermostat T which may be responsive'to the temperature of theair in the enclosure cooled by-the evaporator l4. The there mostat has two sets of contacts, 49 and which are adapted to close as the thermostat responds to successively higher temperatures, which will be assumed to be 76 and 78, respectively. The

contacts 49 are adapted to close the circuit 52 supplying electrical current to the motor I and the contacts 5| are adapted to close a circuit 53 for energizing the solenoid 48.

Operation placingthe conduits 44 and 45 in communication. .Accordingly, suction gas from the compressor" crankcase is communicated through. the conduits Hand 45 and'the passage 46 to the upper end. of the cylinder 3|". The lower side of sure which balances the: suction gas pressure abovethe' piston, so that the spring' 3.4 is effective improve the piston upwardly. Accordingly. suction'gas may flow through the port 22 and the passage 28 to the'associated cylinders.

The refrigerating system operates in the usual manner of such apparatus. vaporized refrigerant 'discharged from theevaporator I4 is passed the piston. 33. isialso. subject to sucti'ongas presthrough the conduit 54, through the casing of v the motor '|'|I, through asuitable manifold in the compressor'cylinder block to the suction passages IR; From thelatter, the suction gas passes through theports'22 and passages 28' to the respective suction valve ports 24. Upon the downstroke of the piston, the gas enters the cylinder and upon the upstroke is discharged through the discharge valve port 25, the chamber 29, and the port 23 to the discharge passage II. It then flows through a suitable manifold passage and the conduit 43 to the condenser It in which it is condensed. Condensed refrigerant is then conveyed'through the conduit 55 and the expansion valve 3,"in which its pressure is reduced and its fidw is regulated; In' the evaporator l4, re-' frig'e'rant isvaporized in extracting heat from the air flowing thereover. The vaporized refrigerant is then discharged to the conduit 54 and V recirculated; In the operation just describedall of the'cylinders are effective tdcompress refrigerant andtbe. system operates at full load.

Assume now that the temperature in the enclosuredrops to 77- degrees, so that the thermostat calls for partial load operation by opening the contacts 5|. The solenoid 48 is deenergized so that'the spring 41 moves the valvefelement 4| to the'left, 'High pressure refrigerant gas is now conveyed through the conduits 43-, 42, and 45 and thepassa'ge 46- to the upper end of the cylinder 3|. 7 Thepressure of this gas is sufficient to overcome the force of the spring 34 and the pressure of the suction gas acting on the lower side of the piston 32. Accordingly, the piston is held firmly against; the upper face of the valve plate or and closes the port 22. Accordingly, the flow of gas to the two associated cylinders is cut ofi.

The refrigerating system now operates in the same 'manner as before except that it operates at only partial capacity, the cylinders associated with the closed port 22 being ineffective to compress refrigerant.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is:

1; In a compressor, the combination of a cylinder member having a cylinder formed therein,

avalve plate closing one end of said cylinder and having a suction valve port in registry with said cylinder and an unloader valve port out of registry with said cylinder, a movable valve element cooperating with said suction valve port to form a suction valve for the cylinder, a cylinder head disposed against the opposite side of said valve plate and having a suction chamber or passage providing communication between said ports inthe valve plate, said cylinder head being formed with a cylinder disposed in alignment with said unloader port, a piston in said cylinder movable-against said valve plate toclose said unloader valve port, and means for admitting fluid pressure to said last-mentioned cylinder to move said piston to closing position;

2. Ina compressor, the combination of a cylinder member having a cylinder formed therein, a valve plate closing one end of said cylinder and having a valve port communicating with the cylinder, a movable valve element cooperating with said valve port to provide a suction valve for the cylinder, a cylinder head disposed against the opposite side of said valve plate, the compressor having a suction passage for conveying suction gas tosaid' valve port, said passage including an unloader valve port and a chamber or passage in said head providing communication between said ports, said cylinder head being formed with a cylinder in alignment with said unloader valve port, a piston in said last-mentioned cylinder movable to and from position closing said un- I loader valve port, means for admitting fluid under pressure to said cylinder to move said piston :to closing position, and a spring biasing said piston to open position.

3. In a compressor, the combination of a cylinder member having a cylinder and a suction passage extending to and opening upon one face thereof, a-valve plate disposed against said face and having an unloader valve port communicating with said suction passage and a valve port communicating with said cylinder, a movable valve element cooperating with the latter port to form a suction valve for the cylinder, a cylinder head disposed against the opposite side of said valve plate and having a suction chamber or passage therein communicating with both of said ports. in the valve plate, an unloader valve member movable into and out of position against the valve plate closing said unloader valve port, and

- means for actuating said unloader valve member, whereby said cylinder may be loaded and unloaded by opening and closing said unloader valve. r

4. In a compressor, the combination of a cylinder member having a cylinder and a suction passage extending to and opening upon one face thereof, a valve plate disposed against said face and having an unloader valve port communicating with said suction passage and a valve port communicating with said cylinder, a movable with said unloader valve port, a piston in said cylinder movable against said valve plate to close said unloader valve port, and means for actuating said piston to and from said closing posipassage therein communicating with both of said 6 tion.

ports in the valve plate, said cylinder head being formed with a cylinder disposed in alignment OLAV SCOTT. 

